Edward weston



(llo lodel.)

E. WESTON.

INOANDESGENT LAMP.

Patented June 6, 1882.

UNITEDSTATES APATENT OFFICE.

EDWARD WESTON, OFV NEWARK, NEW JERSEY, ASSIGNOR TC THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF NEW YORK, N. Y.

INCANDESCENT LAMP.

SPECIFICATION forming part of4 Letters Patent No. 258,966, dated J une 6, 1882. Appnetuon lues Jun-12, rsa1. (No model.)

To all whom t may concern:

Be it known that I, EDWARD waeren, n resident ofNewark, in the county ot' Essex and State of New Jersey, have invented certain new and useful' Improvements in Incandescent Lamps, of which the following is a specication.

The lamps to which this invention relates are those in which a conductor of carbon or being mounted on metallic wires sealed into a transparent receiver from which the air has been as far as possible exhausted. The object of the invention is to produce a more perfect vacuum in the lamps than can be accomplished by the mechanical appliances heretofore used, and bythis means to increase the durability of the lamp, as it is well known that the carbon conductors rapidly disintegrate when heated in the presence of even a'trace of oxygen orair.

In carrying out my invention I make use ot' any ordinary form of incandescent lamp, and in the globe, before it is finallysealed, I introduce a small quantityv ot' a substance possessing the property of absorbing, under certain conditions, air. Such a substance is thorina or thoria, the oxide of the metal thorium, which is used in the following manner: A small quantity being .introduced into the globe, the latter is connected with the airexhaust apparatus,

and while 'the air is being withdrawn the thorina is strongly heated. hen the exhaustion has been carried as far ns possible the heut is withdrawn,the globe detached from the exhunst apparatus and hermeticallyscaled. 0u

cooling, the thorin'aabsorbs the remaining gas or ,air with such avidity as to leave an almost perfect vacuum lin the globe. The substance thoria or thorina whichI utilize for this pur- 4o pose isz as above stated, the only known oxido of thorium, one of the earth metals.

` The preparation of thorina from minerals containing thorium may bc effected in various ways, according to the nature of the substances with which it is associated. From t'borite it may be separated by treating the finely-pulverized ore with hydrochloric acid, evaporatiug to dryness,digesting theresidue with weak "acid in order toseparate the silica, uttering 5o and treating the solution with sulphydric acid to separate lead andtin. The resulting solul*tion-contains the thorium, which may be prelll? similar substance 'is used, the said conductor weak hydrochloric acid and the thorium preci pitated aspotassio-thoriuie sulphate by treatment wit a hot saturated solution of neutral potassio sulphate. The precipitate thus obtained is dissolved in hotI water and treated with ammonia and the resulting precipitate ignited as before. Thorina, when used as above described, is a powerful absorbent of the residual gas in an imperfect vacuum, and as such forms a valuable element in the manufacture of durable incandescent lamps.

The drawing hereto annexed represents an ordinary form of lamp containing the air-absorbent.

A is the globe, which should be ot' such shape as to torm a recess or chamber for coutaining the absorbent; B, the carbon attached to V conductors C C. E is a small quantity of powdered thorinn, which, as stated above, is to be introduced into the globe previously to attachingA the-sume to the air-exhaust apparatus, heated while the withdrawal of airis going on, and then allowed to cool when the lamp has been detached and sealed in the usual manner.

The portion of the globe or lamp in which the air-absorbent is contained is to some extent immaterial, and so,therefore, without limiting myself to the location within the globe of the said absorbent-that is to say. whether it be above or below the caibon conductor, or soA that it will be aected by or protected from' the heat of the same when incandescent- Y What I claim as of my invention is- Au electric lamp consisting of a transparent, exhausted, and hermetically-sealed receiver,'surrouuding a conductor capable of being rendered incandescent, and containing a small quantity of an air-absorbent substance, such asthorina, as and for the purpose set forth.

h Il: testimony whereof I ,have hereunto est my EDWARD WESTON.

Witnesses: Y

` W. SrANLEY, Jr., 'HENRY EINE. v 

